Textbook Question
What is the major product obtained from the acid-catalyzed hydration of each of the following alkenes?
d.
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10. Addition Reactions
Acid-Catalyzed Hydration
4:02 minutesProblem 6a
Textbook Question
Predict the products of the following hydration reactions.
a. 1−methylcyclopentene + dilute acid
Verified step by step guidance1
Step 1: Recognize that the reaction involves the hydration of an alkene using dilute acid. This is an electrophilic addition reaction where water adds across the double bond.
Step 2: Identify the alkene in the structure. The double bond is located within the cyclopentene ring, and the substituent is a methyl group attached to the ring.
Step 3: Understand the mechanism. The dilute acid (H⁺) protonates the double bond, forming a carbocation intermediate. The stability of the carbocation is crucial, and rearrangements may occur to form the most stable carbocation.
Step 4: Predict the regioselectivity of the addition. According to Markovnikov's rule, the hydroxyl group (−OH) will add to the more substituted carbon of the double bond, while the hydrogen (H⁺) will add to the less substituted carbon.
Step 5: Draw the product. The final product will be an alcohol where the −OH group is attached to the more substituted carbon of the original double bond, resulting in 1-methylcyclopentanol.
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Video duration:
4mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Electrophilic Addition
Electrophilic addition is a fundamental reaction mechanism in organic chemistry where an electrophile reacts with a nucleophile, typically involving alkenes. In the case of hydration reactions, the alkene acts as a nucleophile, attacking an electrophilic species, such as a proton from an acid, leading to the formation of a carbocation intermediate.
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Carbocation Stability
Carbocation stability is crucial in predicting the products of reactions involving alkenes. The stability of a carbocation is influenced by its degree (primary, secondary, tertiary) and the presence of electron-donating groups. More stable carbocations are favored during reactions, guiding the formation of the final product in hydration reactions.
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Markovnikov's Rule
Markovnikov's Rule states that in the addition of HX to an alkene, the hydrogen atom will attach to the carbon with the greater number of hydrogen atoms already attached. This principle helps predict the regioselectivity of hydration reactions, indicating that the hydroxyl group will preferentially add to the more substituted carbon of the alkene.
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